docstr: Tests categorical array input and output. 
docstr_tok: ["Tests","categorical","array","input","and","output","."]
code: def test_1_cat_array(self):
      """Tests categorical array input and output."""
      # task: learn to reverse the `arr_len`-length input array.
      df = pd.DataFrame()
      arr_len = 4
      df["input"] = [
          [chr(65 + i + row % 4) for i in range(arr_len)]
          for row in range(200)
      ]
      df["output"] = [
          [chr(65 + i + row % 4) for i in range(arr_len)][::-1]
          for row in range(200)
      ]
      self._test_array(df)
  
file_path: lightwood/tests/integration/advanced/test_array.py
imports: import unittest
  import numpy
  import pandas
  from lightwood.api.types import ProblemDefinition
  from lightwood.api.high_level import json_ai_from_problem, code_from_json_ai, predictor_from_code, predictor_from_problem
label_desc: Use image node_id 3 for calling the TestArrayTarget obj's underlying member method code with example usage: obj.test_1_cat_array() without return types